Eh, all you'd really need is a sufficent length of lever, like three to four inches, and a smooth enough hinge assembly to make it a throwing arm.Then you can say that your Bombed Rock's wings allow him to shave a certain number of inches off his missed shot penalty, seeing as they allow him to be a self guided munition.

And his elbow blades, perfect for charge attacks, parries, or just plain shredding an infantry mob:

Blast, the elder brother with a helluva lot of Dakka:

His two Quad-linked Orange Transparent Gatling Auto Blasters make most enemies chunky salsa:

And the under-slung OT Blasters take care of anything that doesn't require ludicrous amounts of firepower.

Being the elder brother, Blast often has to look out for his younger sibling by shielding him from ranged attacks as they move up.Once they get to the opposition however, he let's Slash do his thing, and has a platform built into the top of his head so his bro can use it as a jumping point: